Dependency Injection in every aspect of a spring app?-Collection of common programming errors

I am taking a look into Spring as a web framework, however I am needing a bit of help getting my head around DI.

The concept of objects getting constructed in the container on run time is such a new concept.

I am just wondering how this will reflect in a big application, would I have some modules doing work that are more highly coupled or should every object be initialised at runtime?

It all seems a little intensive to me, I mean say for example I have a CSV file data mining application that removes the data per row – each rows data is encapsulated in one of my own CSVRow objects for processing or whatever. These objects are instantiated whenever an Excel file maybe uploaded to the server. I don’t know how many I will need to create?

I seem to be getting a bit lost, any clarity, an overview or some guidance would be much appreciated.

Thanks in advance!